The present invention relates to a system for controlling water flow in through open irrigation channels or canals. More particularly, the present invention relates to an automated turnout system for automatically controlling water flow from a main channel.
Open channels are subject to water level fluctuations, which cause water flow to feeder irrigation channels to fluctuate. These fluctuations can cause damage to crops and can waste water. Farmers and irrigation ditch operators have used control gate devices referred to as turnouts to control the flow of water from open channels. These turnouts were not automated and require human operators. These operators have to determine the required flow rate and then set the gate device to the required position. As the main canal or channel and lateral canals or channels fluctuate because of flow changes in the main canal, individual turnouts are subjected to fluctuations because no compensation adjustment is made at the individual turnout. However, the cost of providing a regulation mechanism for each turnout is prohibitively expensive. In this regard, the cost of the gate operator alone is more than farmers can practically afford.
According to the invention, an automated turnout system is provided which can be used to maintain a constant outflow through a farm turnout gate and to help manage water deliveries in open channel systems. The system improves the consistency and dependability of farm deliveries. In addition, the flexibility of the main canal operations is improved because the requirement for constant water levels throughout the canal system is removed and more water is thus available. Because the water is managed better, crops can receive the required amount of water. Further, the flow delivered to the main canal and to the farmers is much closer to that actually required.
In accordance with the invention, an automated turnout control system is provided for controlling the flow of water from a main channel to a turnout channel, the system comprising: a flow measurement structure located in the turnout channel; a water level sensor for measuring the water level at the flow measurement structure and for producing a corresponding output signal; an adjustable flow control gate for controlling the flow of water into the turnout channel from the main channel; a gate actuator for adjusting the gate to an adjusted setting so as to control the flow of water therethrough; a gate setting sensing means for sensing the adjusted setting and for producing a corresponding output signal; and a controller, connected to the water level sensor, gate setting sensing means and gate actuator, for receiving said output signals from the water level sensor and gate setting sensing means and for controlling the gate actuator to adjust the gate setting based on these output signals.
Preferably, the flow control gate comprises a movable gate member movable to a plurality of flow control positions including a fully open position wherein maximum flow is provided and a fully closed position wherein flow is restricted. The gate setting sensing means preferably comprises a position sensor for sensing the position of said movable gate member. Advantageously, the gate comprises a slide gate and the movable gate member comprises a vertically movable gate leaf. The gate actuator preferably comprises a linear actuator for raising and lowering the gate leaf of the slide gate.
The controller preferably comprises a central processing unit. The central processing unit advantageously uses a proportional integral algorithm in controlling said gate actuator. More particularly, the central processing unit advantageously uses a closed loop control algorithm.
The flow measurement structure is located downstream of said flow control gate whereas the water level sensor is located upstream of said flow measurement structure and downstream of the adjustable flow control gate.
In one preferred implementation, the water level sensor comprises an ultrasonic sensor and the flow measurement structure comprises a weir or flume. In another, the flow measurement structure comprises a stilling well and the water level sensor comprises a stilling well mounted string transducer.
Further features and advantages of the present invention will be set forth in, or apparent from, the detailed description of preferred embodiments thereof which follows.